Lost CPU CORES

Hey all,

dmidecode | grep -i CPU
        Socket Designation: CPU 0
        Version: Intel(R) Xeon(R) CPU           E5530  @ 2.40GHz
        Socket Designation: CPU 1
        Version: Intel(R) Xeon(R) CPU           E5530  @ 2.40GHz

cat /proc/cpuinfo | grep -i cpu
cpu family      : 6
model name      : Intel(R) Xeon(R) CPU           E5530  @ 2.40GHz
cpu MHz         : 1600.000
cpu cores       : 1
cpuid level     : 11

I expected 2 cpu's with 8 cpu cores and I have only one !!!

Any idea were to look :wall:

What version of RHEL are you using?

Please post the full output of these commands (without the grep filter in your first post):

dmidecode

cat /proc/cpuinfo 

cat /proc/cpuinfo
 
processor : 0
vendor_id : GenuineIntel
cpu family : 6
model : 26
model name : Intel(R) Xeon(R) CPU E5530 @ 2.40GHz
stepping : 5
cpu MHz : 1600.000
cache size : 8192 KB
physical id : 0
siblings : 1
core id : 0
cpu cores : 1
apicid : 0
initial apicid : 0
fpu : yes
fpu_exception : yes
cpuid level : 11
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 apic mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx rdtscp lm constant_tsc up arch_perfmon pebs bts rep_good xtopology nonstop_tsc aperfmperf pni dtes64 monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr pdcm dca sse4_1 sse4_2 popcnt lahf_lm ida tpr_shadow vnmi flexpriority ept vpid
bogomips : 4801.16
clflush size : 64
cache_alignment : 64
address sizes : 40 bits physical, 48 bits virtual
power management:
 
dimdecode (is quite large)
 
# dmidecode 2.10
SMBIOS 2.6 present.
89 structures occupying 3708 bytes.
Table at 0x0009EC00.
Handle 0x0000, DMI type 0, 24 bytes
BIOS Information
Vendor: American Megatrends Inc.
Version: 'V3.01 '
Release Date: 11/12/2010
Address: 0xF0000
Runtime Size: 64 kB
ROM Size: 2048 kB
Characteristics:
PCI is supported
PNP is supported
BIOS is upgradeable
BIOS shadowing is allowed
ESCD support is available
Boot from CD is supported
Selectable boot is supported
BIOS ROM is socketed
EDD is supported
5.25"/1.2 MB floppy services are supported (int 13h)
3.5"/720 kB floppy services are supported (int 13h)
3.5"/2.88 MB floppy services are supported (int 13h)
Print screen service is supported (int 5h)
8042 keyboard services are supported (int 9h)
Serial services are supported (int 14h)
Printer services are supported (int 17h)
CGA/mono video services are supported (int 10h)
ACPI is supported
USB legacy is supported
LS-120 boot is supported
ATAPI Zip drive boot is supported
BIOS boot specification is supported
Targeted content distribution is supported
BIOS Revision: 8.16
Handle 0x0001, DMI type 1, 27 bytes
System Information
Manufacturer: empty
Product Name: empty
Version: empty
Serial Number: empty
UUID: 03000200-0400-0500-0006-000700080009
Wake-up Type: Power Switch
SKU Number: To Be Filled By O.E.M.
Family: Server
Handle 0x0002, DMI type 2, 15 bytes
Base Board Information
Manufacturer: TYAN
Product Name: S7010
Version: empty
Serial Number: empty
Asset Tag: To Be Filled By O.E.M.
Features:
Board is a hosting board
Board is replaceable
Location In Chassis: To Be Filled By O.E.M.
Chassis Handle: 0x0003
Type: Motherboard
Contained Object Handles: 0
Handle 0x0003, DMI type 3, 21 bytes
Chassis Information
Manufacturer: empty
Type: Main Server Chassis
Lock: Not Present
Version: empty
Serial Number: empty
Asset Tag: empty
Boot-up State: Safe
Power Supply State: Safe
Thermal State: Safe
Security Status: None
OEM Information: 0x00000000
Height: Unspecified
Number Of Power Cords: 1
Contained Elements: 0
Handle 0x0004, DMI type 4, 42 bytes
Processor Information
Socket Designation: CPU 0
Type: Central Processor
Family: Xeon
Manufacturer: Intel 
ID: A5 06 01 00 FF FB EB BF
Signature: Type 0, Family 6, Model 26, Stepping 5
Flags:
FPU (Floating-point unit on-chip)
VME (Virtual mode extension)
DE (Debugging extension)
PSE (Page size extension)
TSC (Time stamp counter)
MSR (Model specific registers)
PAE (Physical address extension)
MCE (Machine check exception)
CX8 (CMPXCHG8 instruction supported)
APIC (On-chip APIC hardware supported)
SEP (Fast system call)
MTRR (Memory type range registers)
PGE (Page global enable)
MCA (Machine check architecture)
CMOV (Conditional move instruction supported)
PAT (Page attribute table)
PSE-36 (36-bit page size extension)
CLFSH (CLFLUSH instruction supported)
DS (Debug store)
ACPI (ACPI supported)
MMX (MMX technology supported)
FXSR (Fast floating-point save and restore)
SSE (Streaming SIMD extensions)
SSE2 (Streaming SIMD extensions 2)
SS (Self-snoop)
HTT (Hyper-threading technology)
TM (Thermal monitor supported)
PBE (Pending break enabled)
Version: Intel(R) Xeon(R) CPU E5530 @ 2.40GHz 
Voltage: Unknown
External Clock: 133 MHz
Max Speed: 2400 MHz
Current Speed: 2400 MHz
Status: Populated, Enabled
Upgrade: Other
L1 Cache Handle: 0x0005
L2 Cache Handle: 0x0006
L3 Cache Handle: 0x0007
Serial Number: To Be Filled By O.E.M.
Asset Tag: To Be Filled By O.E.M.
Part Number: To Be Filled By O.E.M.
Core Count: 4
Core Enabled: 4
Thread Count: 8
Characteristics:
64-bit capable
Handle 0x0005, DMI type 7, 19 bytes
Cache Information
Socket Designation: L1-Cache
Configuration: Enabled, Not Socketed, Level 1
Operational Mode: Write Through
Location: Internal
Installed Size: 256 kB
Maximum Size: 256 kB
Supported SRAM Types:
Other
Installed SRAM Type: Other
Speed: Unknown
Error Correction Type: Parity
System Type: Instruction
Associativity: 4-way Set-associative
Handle 0x0006, DMI type 7, 19 bytes
Cache Information
Socket Designation: L2-Cache
Configuration: Enabled, Not Socketed, Level 2
Operational Mode: Write Through
Location: Internal
Installed Size: 1024 kB
Maximum Size: 1024 kB
Supported SRAM Types:
Other
Installed SRAM Type: Other
Speed: Unknown
Error Correction Type: Single-bit ECC
System Type: Unified
Associativity: 8-way Set-associative
Handle 0x0007, DMI type 7, 19 bytes
Cache Information
Socket Designation: L3-Cache
Configuration: Enabled, Not Socketed, Level 3
Operational Mode: Write Back
Location: Internal
Installed Size: 8192 kB
Maximum Size: 8192 kB
Supported SRAM Types:
Other
Installed SRAM Type: Other
Speed: Unknown
Error Correction Type: Single-bit ECC
System Type: Unified
Associativity: 16-way Set-associative
Handle 0x0008, DMI type 4, 42 bytes
Processor Information
Socket Designation: CPU 1
Type: Central Processor
Family: Xeon
Manufacturer: Intel 
ID: A5 06 01 00 FF FB EB BF
Signature: Type 0, Family 6, Model 26, Stepping 5
Flags:
FPU (Floating-point unit on-chip)
VME (Virtual mode extension)
DE (Debugging extension)
PSE (Page size extension)
TSC (Time stamp counter)
MSR (Model specific registers)
PAE (Physical address extension)
MCE (Machine check exception)
CX8 (CMPXCHG8 instruction supported)
APIC (On-chip APIC hardware supported)
SEP (Fast system call)
MTRR (Memory type range registers)
PGE (Page global enable)
MCA (Machine check architecture)
CMOV (Conditional move instruction supported)
PAT (Page attribute table)
PSE-36 (36-bit page size extension)
CLFSH (CLFLUSH instruction supported)
DS (Debug store)
ACPI (ACPI supported)
MMX (MMX technology supported)
FXSR (Fast floating-point save and restore)
SSE (Streaming SIMD extensions)
SSE2 (Streaming SIMD extensions 2)
SS (Self-snoop)
HTT (Hyper-threading technology)
TM (Thermal monitor supported)
PBE (Pending break enabled)
Version: Intel(R) Xeon(R) CPU E5530 @ 2.40GHz 
Voltage: Unknown
External Clock: 133 MHz
Max Speed: 2400 MHz
Current Speed: 2400 MHz
Status: Populated, Enabled
Upgrade: Other
L1 Cache Handle: 0x0009
L2 Cache Handle: 0x000A
L3 Cache Handle: 0x000B
Serial Number: To Be Filled By O.E.M.
Asset Tag: To Be Filled By O.E.M.
Part Number: To Be Filled By O.E.M.
Core Count: 4
Core Enabled: 4
Thread Count: 8
Characteristics:
64-bit capable
Handle 0x0009, DMI type 7, 19 bytes
Cache Information
Socket Designation: L1-Cache
Configuration: Enabled, Not Socketed, Level 1
Operational Mode: Write Through
Location: Internal
Installed Size: 256 kB
Maximum Size: 256 kB
Supported SRAM Types:
Other
Installed SRAM Type: Other
Speed: Unknown
Error Correction Type: Parity
System Type: Instruction
Associativity: 4-way Set-associative
Handle 0x000A, DMI type 7, 19 bytes
Cache Information
Socket Designation: L2-Cache
Configuration: Enabled, Not Socketed, Level 2
Operational Mode: Write Through
Location: Internal
Installed Size: 1024 kB
Maximum Size: 1024 kB
Supported SRAM Types:
Other
Installed SRAM Type: Other
Speed: Unknown
Error Correction Type: Single-bit ECC
System Type: Unified
Associativity: 8-way Set-associative
Handle 0x000B, DMI type 7, 19 bytes
Cache Information
Socket Designation: L3-Cache
Configuration: Enabled, Not Socketed, Level 3
Operational Mode: Write Back
Location: Internal
Installed Size: 8192 kB
Maximum Size: 8192 kB
Supported SRAM Types:
Other
Installed SRAM Type: Other
Speed: Unknown
Error Correction Type: Single-bit ECC
System Type: Unified
Associativity: 16-way Set-associative
Handle 0x000C, DMI type 8, 9 bytes

Question: where does this assumption come from? (hardware spec, I guess?).

Thanks,
/Lew

the 5530 has 4 cores and if there are 2 of them there should be 8 cores. Before I installed Linux on this box I had windows installed and there where 8 cores.

If you see Linux find 2 CPU's in the worst case there should be 2 cores but linux find still only one.

Again, what version of red hat are you running?

TYAN S7010 two E5530 (4 cores each) on RHEL 6.1 x64

Have you checked the output from cpuid and acpidump?

OK, run this command:

zgrep SMP /proc/config.gz

The output should have CONFIG_SMP=y if your SMP support is enabled; that is if your kernel has support for /proc/config.gz. If it does not, there will be an error which tells you nothing.

OBTW, as I recall, most Linux distributions do not come with an SMP enabled kernel; so you will most probably need to create one. Configure a new kernel and answer Y to CONFIG_SMP.

The default kernel for RHEL does include SMP. If someone mucked about, however that could explain it. I would just like to be sure the user is using RHEL 6.1 and not RHAT 6.1.

We can also confirm/check for SMP with uname -a . Here is an example:

$ uname -a
Linux www 2.6.31-15-server #50-Ubuntu SMP Tue Nov 10 15:50:36 UTC 2009 x86_64 GNU/Linux

So, please post the output of uname -a .

On Fedora and downstream, the file you probably want is /boot/config-<name of your kernel>. Also CONFIG_SMP is Y by default - at least on AMD64 (x86_64) platforms. For example, I am using 2.6.40 on a F15 X32 development system, so the name of the configuration file is config.2.6.40.4-5.fc15.x32. (x32 is not a typo, it is a new emerging psABI)

If the OP installs and runs cpuid, we will have a much better idea of what the actual cpus think they are. I suspect that cpuid will return the expected values but I think we should eliminate this possibility or that some cores have been disabled by the BIOS. BTW, There was an interesting discussion on FreeBSD back in 2010 re E5530s and missing cores. Search for "FreeBSD, E5530 cpuid acpidump." Turns out that the missing cores were disabled by a BIOS setting.

What if someone replaced the kernel without replacing the config? /boot/config-* might lie, but /proc/config.gz won't...

As far as I recall there is no /proc/config.gz in RHEL. I am not in front of a RHEL 6.1 box at the moment but looking at a CentOS 5.6 and a Fedora 15 box, I do not find a /proc/config.gz.

Try modprobe config if you don't have it.

It is probably quicker and easier to simply do a uname -a and check for SMP support.

OBTW, I just noticed that, at least on Ubuntu, the config file is in /boot, example:

$ grep CONFIG_SMP config*
config-2.6.24-19-server:CONFIG_SMP=y
config-2.6.31-15-server:CONFIG_SMP=y
$ 

Huh?